A Blue View: 10 Things You Didn’t Know About Jellyfish

These gelatinous animals are more fascinating than you think. To prove it to you, we’ve collected some of the coolest facts guaranteed to give you a whole new perspective on jellies:

Published March 25, 2015

1. Not all jellyfish emerge in the summertime.

The lion’s mane jelly is called the “winter jellyfish” for a reason. You can find these jellies in our own Chesapeake Bay in November through March.

2. A group of jellyfish is called a smack.

Other common collective names for these creatures include “bloom” and “swarm.”

3. Some jellies can glow in the dark.

For example, the comb jelly—found right here in the Chesapeake Bay—uses bioluminescence to light up when disturbed at night.

4. Jellyfish don’t have brains.

There’s not much to a jellyfish. They’re composed of three layers: an outer layer called the epidermis; a thick, elastic layer made of a jelly-like substance called mesoglea; and an inner layer called the gastrodermis.

5. Jellies have traveled to space.

Moon jellies flew aboard the space shuttle Columbia during a 1991 study on weightlessness and the development of juvenile jellyfish.

6. Jellies can be huge!

The largest recorded Lion’s mane jellyfish had tentacles reaching 120 feet in length, making it one of the longest known animals in the world!

7. Jellyfish are about 95 percent water.

In comparison, humans consist of about 65 percent water.

8. They might hold the key to immortality.

The Turritopsis dohrnii, also known as the “immortal jellyfish,” can transform itself back into a polyp—its earliest stage of life—to begin its life cycle all over again.

9. Jellies do great things!

They’re a food source for many larger animals, including fish, crustaceans and sea turtles.

10. You can touch jellies at the National Aquarium!

Living Seashore, our exhibit opening this May, will give guests the opportunity to actually touch the pulsing bell of a moon jelly in one of our two touchpools!

To learn more about these fascinating aquatic animals, listen to this week's A Blue View podcast: